I think it depends on the yoga focus for the day. Today's was Strength in Stillness and it was challenging to hold longer poses and balance, too. I'm very happy to add more yoga/stretch into my life, and it's much needed.
Jessica probably eased up on the rotation somewhat realizing people are busy with family activities during the Summer months. Also, she's made the rotation very flexible so you can choose what you want to do on the alternate strength days, if you want. Adding more walking, yoga or whatever.